If you have big biceps, a new study claims you're more prone to hold Republican views on economic redistribution.

Researchers published their findings on May 13 in Psychological Science that explained how political opinions on redistribution of wealth are evolutionarily tied to upper-body strength.

"While many think of politics as a modern phenomenon, it has -- in a sense -- always been with our species," said Michael Bang Petersen, co-author of the study and associate professor at Aarhus University's School of Business and Social Sciences.

When early ancestors roamed the lands, allocation of resources was not argued before courts or signed into law. Back then, individuals with physical strength dominated and made the final decisions.

Researchers thus determined that upper-body strength would represent men's ability to defend or acquire resources.

In the study, researchers gathered information on bicep size, socioeconomic backgrounds, and support for economic reallocation, from approximately 1,300 men and women from the United States, Argentina, and Denmark.

The men and women were asked whether they agree or disagree with several questions about redistribution. As predicted, researchers found wealthy men with more upper-body strength were less likely to support the redistribution idea, while less wealthy men with weaker upper-body strength would be in favor of economic redistribution. No significant correlation was made between strength and redistribution support for women because throughout evolutionary history, women had more to lose than gain if they engaged in brawls.

"Despite the fact that the United States, Denmark and Argentina have very different welfare systems, we still see that -- at the psychological level -- individual's reason about welfare redistribution in the same way," said Petersen. "In all three countries, physically strong males consistently pursue the self-interested position on redistribution."

Researchers also discovered that weaker men are not as willing to support their own self-interest. However, if you're weak and rich, you're less resistant to redistribution.

"Our results demonstrate that physically weak males are more reluctant than physically strong males to assert their self-interest -- just as if disputes over national policies were a matter of direct physical confrontation among small numbers of individuals, rather than abstract electoral dynamics among millions," said Petersen.

Overall, this study can predict what the political motivations are for men. Past studies have never been able to predict political motivation using economic redistribution or any economic model.

"This is among the first studies to show that political views may be rational in another sense, in that they're designed by natural selection to function in the conditions recurrent over human evolutionary history."

Source: Peterson MB, Sznycer D, Sell A, et al. The ancestral logic of politics: Upper-body strength regulates men's assertion of self-interest over economic redistribution. Psychological Science. 2013.